Digital Thermostat

[Jd67]

I am thinking of changing from old thermostat to digital. There are 3 wires in old one but only need 2 in digital. The grey wire is not needed what is grey wire for

 

[ShaunCorbs]

You should have

Live Brown or red
Neutral Blue or black
Earth Copper/ earth sleeve
And switch live/ call for heat grey

These should be right but either get a spark or heating eng to confirm

 

[Jd67]

Salus RT300 Digital Room Thermostat £25 What is this thermostat from B&Q like compared to this Honeywell THR840 also from B&Q £35

 

[newcastle phill]

I cant comment on the honeywell but ive fitted loads of salus rt300/500 and not had a problem.
They are cheap functional and if installed correctly in a smaller property (i.e not a 3 storey monster) they work just fine when installed and frequency set correct

 

[Jd67]

Thank you for your help

 

[Jd67]

Just purchased the Salus RT500 Digital Room Thermostat. 2 wires one L other SL What is the SL

 

[Howsie]

Switched live. Basically your thermostat will close this (send current) down the SL to tell the boiler to fire up.

 

[Jd67]

Help. Can't figure out wiring. Old manual one wiring was Brown live into no1-Grey into no3- Black into no 4. When power is on there is power in brown and grey. Nothing in black. The digital has 2 wires Live goes to Live but which wire Grey or Black goes to SL. Tried Grey in it but heat will not switch on. Afraid to connect Black incase something fuses.
May have to get electrician although had hope to cut cost.

 

[Gasmk1]

if you have 3 wires one will be live from the boiler the other will be switch live back to the boiler (call for heat) the other will probably be a neutral, but if you are not sure and cant use an electrical multimeter to check then you need to get either a gas engineer or and electrician to do it for you

 

[PhoenixServices]

Brown is your permanent live
Grey Sl
And black either neutral or earth

 

[GasmanxxxR1]

Most old thermostats were 'in' on 1 and 'out' on 3 so i would say Grey should be SL, when you tested it did you have timer calling for heat?

 

[drip-dry]

It should be mentioned that if you get it wrong you could cause ££££££ of damage to your boiler/system controls....grey pink blue or fluffy dice...you should check the source of each cable...I could probably tell you from what you described which is which but in the same breath have come acoss many installations were it has been done by a colour blind dyslexic while viewing stat through a mirror ...

 

[Jd67]

Most old thermostats were 'in' on 1 and 'out' on 3 so i would say Grey should be SL, when you tested it did you have timer calling for heat?

I tried Grey and black seperate but nothing happened. I am thinking of changing to a simpler digital because this Salus RT500 is a bit complicated for us. Will try wireing again

 

[GasmanxxxR1]

The rt500 is a programmable room stat, What type of boiler/system do you have.

You will more than likely need to place the receiver near the wiring centre and re-wire the system somewhat.

You may need just a basic room stat with batteries for the display and 2 wires to control the heating

Honeywell DT90E Digital Room Thermostat + ECO | Thermostats | NoLinkingToThis

like this

 

[Jd67]

Thank you yes that looks like the one. Picture of what I have at present Sunvic Which wire goes from Sunvic to the digital

 

[Jd67]

Honeywell thr840duk+eco digital room thermostat Fitted this one okay and working only problem is the clicking noise. Alright through the day but at night it is loud. We are both light sleepers. Can anything be done about this

 

[Gasmk1]

no. thats is the way it works

 

[ShaunCorbs]

unless you have the heating through the night it shouldn't active the relay etc